Arrangement in breathing apparatus for use under water



y 1959 M. M. ARBORELIUS ETAL 2,896,616

ARRANGEMENT IN BREATHING APPARATUS FOR USE UNDER WATER Filed July s, 1956 ATTORNEK United States Patent O In breathing apparatus for under-water use which are provided with a breathing bag, the bag will be at a different depth from the lungs of the diver when the diver takes certain positions in the water. When the breathing bag, for instance, is higher than the lungs it is exposed to a smaller hydrostatic pressure than that acting on the divers chest. This pressure difference causes the air in the divers lungs to have a lower pressure than the water surrounding the chest, which gives rise to a tiring resistance to inhalation, which, in the case of a strained heart, may cause death from acute heart dilatation. .On the other hand, if the breathing bag is at a greater depth than the divers lungs, a higher pressure will obtain in. the lungs than in the water around the chest, which like-;

2,896,616 i atented July 28, 1959 larger than on the breathing bag. This pressure difiierence has been compensated for in the embodiment shown by means of a weight 7 attached to the movable wall 3. This weight gives rise to a force 8, which is directed downwardly and therefore loads the breathing bag, causing the pressure within it to increase. Obviously, the size of the weight as well as its position can be chosen in such a way as to compensate fully for the pressure difference referred to. In order for the weight to have as small a volume as possible, it is suitable to place it at a considerable distance from the hinge connection 4, preferably at the edge of the movable wall 3 farthest away from the connection and possibly on an arm exwise impairs breathing in that a tiring resistance to ex-i halation arises. This entails the risk of a severe reduction of the venous return flow to the heart.

These conditions have hitherto not been taken into account and no method has therefore been available for eliminating the breathing difliculties to which a diver carrying the type of breathing apparatus referred to has been exposed in some positions taken during the diving operation.

The present invention, which is intended to remove the ditficulties mentioned, is characterized by an arrangement for compensating for the pressure difference between the divers lungs and the breathing bag caused by the diiference in hydrostatic pressure exerted on the divers chest and on the breathing bag owing to diflFerent depth positions of the chest and the breathing bag. The arrangement may comprise, in principal, means for operating on the breathing bag so as to load it with a force which is added to the hydrostatic pressure on the breathing bag when the latter is above the chest and which relieves the breathing bag to a corresponding degree when the latter is below the chest. In a particularly simple embodiment of the invention, the arrangement comprises a weight, which is connected with a wall of the breathing bag.

The invention is applicable to apparatus provided with breathing bags of any suitable construction but has particular advantages with regard to the simplicity and suitability of the design when applied to breathing bags with rigid walls. In an apparatus of that kind, the breathing bag may be constructed with at least two rigid walls, which are connected together in the manner of a hinge. The compensation to be achieved by the invention can then be obtained in a simple manner by means of a weight attached to one of the rigid walls, namely the one farthest away from the diver in the operative position of the apparatus.

The invention is further illustrated by an embodiment shown on the attached drawing. Fig. 1 shows the apparatus mounted on a diver in a prone position and Fig. 2 similarly with the diver in a recumbent position.

As shown on the drawing, the breathing bag 1 of the apparatus comprises a bellows having two rigid walls 2, 3, which are joined together along an edge thereof by means of hinges 4. One wall 2. is intended in the operative position to rest on the back of the diver 5, whereas the other wall 3 is movable on the hinge connection 4 towards and away from the first-mentioned wall 2.

In the position shown in Fig. 1, the lungs 6 of the diver are at a greater depth than the breathing bag 1 and the hydrostatic pressure on the chest is therefore tending from the said edge.

In the recumbent position shown in Fig. 2, in which the breathing bag 1 is at a greater depth than the lungs 6 of I the diver, the movable wall 3 is turned downwardly andfthe weight 7 in this case causes a force 8, which relieves the breathing bag and decreases the pressure therein. In this case also, a compensation is thus obtained for the'higher hydrostatic pressure to which the breathing bag is exposed in comparison with the divers chest.

The invention is not limited to pressure compensation through the use of a weight, it being also possible to use instead thereof an elastic force operating on the breathing bag, for instance the force of a metallic spring, a rubber band or the like. The invention is also applicable to breathing bags with flexible walls. The invention is primarily intended for use in oxygen breathing apparatus but is not limited to this application, being also applicable to other breathing apparatus for under-water use.

What we claim is:

1. An oxygen breathing apparatus for under-water use, comprising a breathing bag which is provided with loading means responsive to the position of the breathing bag with respect to the diver wearing said bag for compressing the breathing bag when the breathing bag is above the chest of the diver and for expanding the breathing bag when the breathing bag is below the chest of the diver so as to compensate for the difierence between the hydrostatic pressure acting on the breathing bag and the divers chest owing to diiterent depth positions thereof, said means being connected with one rigid wall of a breathing bag comprising two rigid walls connected together in the manner of a hinge.

2. An oxygen breathing apparatus according to claim 1 wherein said means is connected with the edge of the rigid wall farthest away from the hinge connection.

3. An oxygen breathing apparatus for under-water use, comprising a breathing bag which is provided with elastic loading means acting upon a wall of the breathing bag and responsive to the position of the breathing bag with respect to the diver wearing said bag for compressing the breathing bag when the breathing bag is above the chest of the diver and for expanding the breathing bag when the breathing bag is below the chest of the diver so as to compensate for the diiference between the hydrostatic pressure acting on the breathing bag and the divers chest owing to different depth positions thereof.

4. An oxygen breathing apparatus according to claim 1 wherein said means consists of a weight attached to a wall of the breathing bag.

FOREIGN PATENTS Germany May 28, 1953 

